scholarly journals Effects of Powder Feeding Rate on Formation of Nickel Ultrafine Particles Using RF Plasma Method

2004 ◽  
Vol 41 (10) ◽  
pp. 722-729 ◽  
Author(s):  
Katuo Saitou ◽  
Akira Suzuki
Keyword(s):  
Ultrafine Particles ◽  
Feeding Rate ◽  
Rf Plasma ◽  
Plasma Method ◽  
Powder Feeding

Direct energy deposition metamodeling using a meshless method

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Boussad Abbes ◽  
Tahar Anedaf ◽  
Fazilay Abbes ◽  
Yuming Li
Keyword(s):  
Surrogate Model ◽  
Manufacturing Process ◽  
Laser Power ◽  
Energy Deposition ◽  
Feeding Rate ◽  
Maximum Temperature ◽  
Direct Energy Deposition ◽  
Content Type ◽  
Direct Energy ◽  
Powder Feeding

Purpose Direct energy deposition (DED) is an additive manufacturing process that allows to produce metal parts with complex shapes. DED process depends on several parameters, including laser power, deposition rate and powder feeding rate. It is important to control the manufacturing process to study the influence of the operating parameters on the final characteristics of these parts and to optimize them. Computational modeling helps engineers to address these challenges. This paper aims to establish a framework for the development, verification and application of meshless methods and surrogate models to the DED process. Design/methodology/approach Finite pointset method (FPM) is used to solve conservation equations involved in the DED process. A surrogate model is then established for the DED process using design of experiments with powder feeding rate, laser power and scanning speed as input parameters. The surrogate model is constructed using neutral networks (NN) approximations for the prediction of maximum temperature, clad angle and dilution. Findings The simulations of thin wall built of Ti-6Al-4V titanium alloy clearly demonstrated that FPM simulation is successful in predicting temperature distribution for different process conditions and compare favorably with experimental results from the literature. A methodology has been developed for obtaining a surrogate model for DED process. Originality/value This methodology shows how to achieve realistic simulations of DED process and how to construct a surrogate model for further use in optimization loop.

TiC Reinforced Steel Matrix Composite Layers Produced by Laser Surface Alloying

2008 ◽  
Vol 59 ◽  
pp. 55-61 ◽  
Author(s):  
A. Fernández-Vicente ◽  
G. Castro ◽  
J.L. Arias ◽  
Maria Angeles Montealegre
Keyword(s):  
Wear Resistance ◽  
Feeding Rate ◽  
Laser Surface ◽  
Beam Power ◽  
Powder Injection ◽  
Steel Matrix ◽  
Surface Alloying ◽  
Feeding Rates ◽  
Laser Surface Alloying ◽  
Powder Feeding

In the present work, laser surface alloying of H13 tool steel by using TiC has been performed by means of DHPDL (Direct high power diode laser). Different layers were produced by varying laser beam power and powder feeding rate. Several alloying degrees were obtained depending on the laser parameters employed. Laser surface alloyed layers were analyzed by using optical and scanning electron microscopy. Wear resistance was evaluated through pin-on-disk tests at room temperature. In general, it was observed that dilution of TiC powders into the molten H13 substrate decreased as the powder-feeding rate increased and particles size of the titanium carbide precipitates was larger for the higher feeding rates. Wear measurements showed lower values for the wear resistance coefficient of laser alloying layers produced at higher values of the powder injection (feeding) rate. Analysis of the wear surface track was conducted and the specific contribution of the microstructural features on the wear coefficient was assessed. Thus, it was found that larger particles sizes and particle contents protected the martensitic and dendritic steel matrix from being deeply worn. Lower TiC contents in the alloyed layer gave rise to a higher contribution of the plastic deformation in the wear track.

Evaluation of the Stability and Precision of Powder Delivery during Laser Additive Manufacturing

2013 ◽  
Vol 380-384 ◽  
pp. 4348-4352
Author(s):  
Kai Zhang ◽  
Lei Wang ◽  
Xiao Feng Shang
Keyword(s):  
Laser Beam ◽  
Molten Pool ◽  
Gas Flow ◽  
Feeding Rate ◽  
Shielding Gas ◽  
Metal Parts ◽  
Deposited Metal ◽  
Computer Aided ◽  
The Stability ◽  
Powder Feeding

The fabrication of metal parts is the backbone of the modern manufacturing industry. Laser forming is combination of five common technologies: lasers, rapid prototyping (RP), computer-aided design (CAD), computer-aided manufacturing (CAM), and powder metallurgy. The resulting process creates part by focusing an industrial laser beam on the surface of processing work piece to create a molten pool of metal. A small stream of powdered alloy is then injected into the molten pool to build up the part gradually. By moving the laser beam back and forth and tracing out a pattern determined by a CAD, the solid metal part is fabricated line by line, one layer at a time. By this method, a material having a very fine microstructure due to rapid solidification process can be produced. In the present work, a type of direct laser deposition process, called Laser Metal Deposition Shaping (LMDS), has been employed and developed to fabricate metal parts. In the LMDS process, the powder delivery system is an important component to perform the powder transport from powder storage box to powder nozzle, which supplies the raw material for the as-deposited metal parts. Consequently, the stability and precision of powder delivery during LMDS is essential to achieve the metal parts with high quality, so it is critical to evaluate the main factors closely related to the stability and precision of powder delivery. The shielding gas flow and the powder feeding rate were ascertained through experimental measure and formula calculation. The results prove that the suitable shielding gas flow and powder feeding rate can promote the stability and precision of powder delivery, which is the basis for the fabrication of as-deposited metal parts with flying colors.

Characterization of Spherical Molybdenum Powders Prepared by RF Plasma Processing

2012 ◽  
Vol 482-484 ◽  
pp. 2563-2567 ◽  
Author(s):  
Yan Wei Sheng ◽  
Zhi Meng Guo ◽  
Jun Jie Hao
Keyword(s):  
Feeding Rate ◽  
Morphological Properties ◽  
Narrow Particle Size Distribution ◽  
Rf Plasma ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Spheroidization ◽  
Powder Characteristics ◽  
Near Net Shape

Spherical molybdenum powders were synthesized by (RF) plasma with irregular molybdenum powders. The powder characteristics and spheroidization efficiency of the feeding rate for obtain the spherical molybdenum powders were studied. The phase composition and morphological properties of the powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). As a result, the fine spherical powders composed of pure molybdenum with favorable dispersity and its surface became smooth. The spheroidization efficiency of synthesized powders was almost 100 % at feeding rate of 5g/min. LMS analysis indicated that the as-prepared powder had narrow particle size distribution and the spheroidization efficiency of the sample decreases gradually as increasing of the feeding rate. The RF plasma spheroidization of molybdenum powder is an ideal route synthesis of well- spherical molybdenum powders used as near net-shape technology and powder metallurgy.

scholarly journals Processing of Superfine and Ultrafine Phosphate of a Phosphomud (Part Two)

2019 ◽  
Vol 9 (2) ◽  
pp. 102
Author(s):  
Suzan S. Ibrahim ◽  
Khaled E. Yassin ◽  
Tawfik R. Boulos
Keyword(s):  
Ultrafine Particles ◽  
Feeding Rate ◽  
Separation Efficiency ◽  
Water Pressure ◽  
Rotation Frequency ◽  
Variable Frequency Drive ◽  
Phosphate Industry ◽  
Irreversible Effect ◽  
Mineral Industries ◽  
Central Composite

Mineral industries in common generate a lot of rejects in the form of fines and slimes, which ultimately create environmental and social problems besides causing losses of mineral values. In view of the recent stringent policy imposed on the environment, there is an urgent need to attempt possible simple and cheap solutions to such problems. These slimes have long been considered in the industry to be unrecoverable. It has been standard practice over many years in the phosphate industry to separate and discard the fines and ultrafine particles. In this respect, the present study shed light on the recovery of super and ultrafine phosphate of a phosphomud produced after the processing of an East Mediterranean phosphate ore. Falcon Concentrator model SB40-VFD (semi-continuous with variable frequency drive) was used in this study to recover the -32 micron phosphate fines of D50=11 micron. The effect of the main variables of the semi-continuous Falcon concentrator model SB40-VFD, including the bowl rotation frequency Hz, the fluidizing water pressure psi, and feeding rate g/min on the separation efficiency were followed up. In addition, two feeding modes based on a particle size-by-size were tried in this study: The sample was fed as a global -32 micron sample or as two fractions, -32+11 micron, and -11 micron samples. Central Composite Rotatable Design (CCRD) was applied on the Falcon separation of the -11 micron fraction with D50 < 3 micron alone to model and optimize the separation process for the two responses: the recovered phosphate grade and recovery. Results showed that the phosphate fines containing 14.73% P2O5, 15.03% acid insoluble, and 19.07% loss in ignition was recovered with grade and P2O5 recovery reaching 28.29%, and 95.97% in case of separating the overall -32 micron sample as one feed. In case of the fractionated feeding samples, the total grade and recovery reached 29.21%, and 88.42%, respectively. The application of the CCRD results showed that the bowl rotation frequency showed to have the main irreversible effect on the product grade, where the fluidizing water pressure had the main reversible effect on the recovery. On the other hand, feeding rate showed some effect on the product grade with almost no effect on its P2O5 recovery%.

scholarly journals Effect of Powder Feeding Rate on the Forming Quality of Alloy by Laser Melting Deposition

2021 ◽  
Vol 2083 (2) ◽  
pp. 022024
Author(s):  
Chenghong Duan ◽  
Yinzhou Zhang ◽  
Xiangpeng Luo
Keyword(s):  
Surface Quality ◽  
Feeding Rate ◽  
Granular Bainite ◽  
Single Track ◽  
Laser Melting ◽  
Forming Quality ◽  
Metallurgical Bonding ◽  
Laser Melting Deposition ◽  
Powder Feeding

Abstract 12CrNi2 alloy steel was prepared by Laser Melting Deposition (LMD) technology, and the effect of powder feeding rate on surface quality, internal defects, microstructure, and microhardness of the single track and manufactured part were investigated. The results show that the metallurgical bonding of the single track deteriorates, the surface quality of the manufactured part is improved, the average microhardness of the manufactured part increases, and the number of pores first decreases and then increases with the increase of powder feeding rate. At the lower powder feeding rate, the manufactured parts have larger pore defects, while at the higher powder feeding rate, the manufactured parts have poor fusion defects. The main phase composition of the manufactured parts is ferrite(F), granular bainite (GB), and pearlite(P), and the manufactured part has finer grains at the higher powder feeding rate.

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